Heretofore, tablets for oral administration which have a circular (spherical, disk-like) shape or an irregular (football-like, oval or triangular) shape have been commercially available. To tablet magnesium oxide particles, for example, there are known methods of tableting a blend of magnesium oxide particles, a binder and a disintegrating agent (Patent Documents 1 and 2). Since the tablets obtained by these methods have relatively high contents of the binder and the disintegrating agent, the content of the magnesium oxide particles in the tablets is not so high. These tablets have a long disintegration time in the oral cavity and are difficult to be taken when they are administered orally.
In contrast to this, there is proposed a tablet which has a high content of magnesium oxide particles and a short disintegration time (Patent Document 3). This tablet contains 88 to 97 wt % of magnesium oxide particles, has a very short disintegration time of less than 10 seconds and is easy to be taken. This Patent Document 3 teaches that this tablet has a diameter of 5 to 12 mm and a thickness of 2 to 6 mm but is silent about its shape.